1. Field of the Invention
The present invention relates to a system and a method for viewing a pair of electronic represented images, in total and at the same time. The system has the added advantages of presenting images of differing resolution and can be interactive in nature.
2. Description of the Related Art
There has long existed a need for an image display system that would allow a viewer to view more then one artificial image at a time. A variety of approaches have been employed with limited success in an attempt to find a solution to this problem. One solution was to use multiple displays. This was achieved by placing two or more displays adjacent to one another and located within the same plane. While this approach did permit viewing of more than one image, as the displays became larger, concurrent viewing became more and more difficult primarily due to the distance between the images. In an attempt to remedy this problem, systems were developed that produce multiple images from a single source, for example, picture-in-picture (PIP) displays or by the use of "windowing" techniques.
In a windowing approach, a viewer who wants to see a second image selects the image, and it in turn is embedded within the first image on the same display. The second image, depending upon its size and shape, blocks all, or a portion of the first image. The PIP approach is quite similar to windowing. In a PIP system, a second image is projected onto the display replacing a portion, if not all of the first image, giving the effect that it is embedded within a first image. Because both the PIP and the windowing approaches result in some degree of blocking of a first image by a second image, true concurrent viewing cannot be achieved. Additionally, both PIP and windowing approaches are limited to the maximum resolution of the display, in that the maximum resolution of either image is constrained by the resolution capabilities of the display itself. While higher resolution displays do exist, such displays are quite costly. In addition, as displays size increases, performance is generally sacrificed. This is due to both system optics and the fact that as one moves radially outward from the center of the display the resolution capabilities of the system generally decrease.
Other systems do exist that permit concurrent viewing of images. However, those systems do not consist of two electronically generated displays, but consist of one electronically generated display, and a real world view. Additionally, with such systems the viewer is only able, at best, to control the image presented by the artificial display, not the image of the real world. An example of such a system is a "head-up display" (HUD). HUD systems have been used in automobiles and aircraft. In a HUD system a transparent surface is placed in front of the viewer who looks through it and sees the electronically generated image superimposed on the natural view of the outside world. In aircraft, HUD displays are generally used to provide navigation and weapons information to the pilot. The displays are commonly mounted on the aircraft canopy, or separate beamsplitter surface, and located directly in front of the pilot. The display superimposes its information on the pilots view of outside world. Thus, a pilot flying the plane looks through the display and sees not only the view in front of the aircraft, but also the data presented by the HUD display. The pilot has control only over the information presented by the HUD display, and is able to select a superimposed image for viewing from one of several instruments or systems on board the aircraft. However, the pilot does not have control over the natural view presented by the outside world, and at best could only change the natural view by repositioning the aircraft.
The HUD systems used in automobiles are similar to those used in aircraft, but are generally more restrictive. In an automobile, these systems are used to display speed, fuel or directional information, for example. However, more advanced systems have been developed for law enforcement application, see Eye of the Law, Vectors, Vol. XXXV, 2, 10-12, 1993. While these systems do have additional capabilities they are still limited to display of information from preselected instruments or other systems.
Similar to the aircraft system, the HUD system for automobiles provides its data superimposed on the drivers view of the outside world. However, in an aircraft the superimposed information is focused to infinity, whereas in an automobile the image appears to originate from a location above the automobile's front bumper. As in an aircraft, the driver of the automobile sees both the view in front of the automobile and the superimposed information provided by the HUD display. Thus, at best, the driver has control over the information presented by the HUD display and would likely be limited to a few predetermined instruments or systems for viewing.
In addition, the resolution capabilities of both the aircraft and automobile HUD systems are set by the respective system themselves, with the viewer having no control over the resolution of the natural image. Such systems generally provide only monochrome display and are not interactive in nature in that they only provide predetermined types of information.